Apple only allows you to flash iOS versions they are currently . Go to IPSW.me. Select your device. If the version is Red , you cannot request SHSH for it. You must download a Green (signed) version. 2. Verify Your Internet & Connection
: Outdated software is a primary cause. Download and install the newest version from the official 3uTools website to resolve known bugs with SHSH requests. how to fix error unable to request shsh on 3utools when upd
This error stops the restore process immediately. It is frustrating, especially if you are stuck in a boot loop or trying to downgrade iOS. Apple only allows you to flash iOS versions